Conduit coupling



March 17, 1931. J PEARSON 1,796,806

CONDUIT COUPLING Filed Feb. 2. 1928 j 1 51x125. 8 62% @M ATTORNEY.

' 20 outlet Patented Mar. 17,1931.

UNITED, STATES PATENT OFFICE JOHN T. PEARSON, OF SYRACUSE, NEW YORK, ASSIGNOR T CROUBE-BIINDS COMPANY,

OF BYBACUSE, NEW YORK, A CORPORATION OF NEW YORK CONDUI'I' COUPLING Application filed February 2, 1828. serial No. 251,237.

This invention relates to conduit couplings particularly means for coupling electrical conduits or of coupling an electrical conduit to a box as an outlet box connected in the conduit system and has for its 0b180l3,

a particularly slmple and efiicient means by which the conduit can be coupled to a box or to another conduit without being threaded and means by which the conduit can not be loosened from the conduit by the turning of the conduit.

The invention consists in the novel. features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate correspondingparts in all the views.

Figure 1 is a side elevation of a conduit box and conduit providedwith this con ling. p

U igure 2 is a fragmentary detail view of a conduit end with the nut of the coupling thereon, the nut beingpartly in section.

Figure 3 is an elevation partly in section ofthe contractile collar showing the same in juxtaposition to the conduit shown in Fi re 1. f I f i e lis a re enta eevation o a 80cond1 1 it outlet box h ging a ihreaded nipple, the same bein shown in juxtaposition to the collar of igure 3 and the conduit end and nut of Figure 2 before the parts are 3 brought together. 85

collar.

Figure 6 is an enlarged sectional view through the assembled conduit end, outlet box and couplin Figures 7 and 8 are respectively an end view and side elevation of a nut.

Figure 9 is an end viewof the conduit outlet box showing an end elevation and the body of the coupling associated with the box.. V 1

This couplin particularly adapted for use on threa less conduit ends because there are no threads to hold the conduit rigid. It is necessary that the conduit without threads be clamped rigidly and that the to being capable of di Flgure 5 is an elevation of the contractile clamping means compensate for variations within limits in the diameter and the contour of the conduit.

In commercial conduits, the normal diameters vary, conduits the normal diameter is .840 and these conduits have been found to vary from a minimum of .825 to .855.

Also, it is necessary that the coupling must clamp the conduit with sufiicient rigidity to prevent sagging of the conduit line even thou h it is insulficiently supported. Also, the (damping means must tightly grip the conduit and not be loosened even though the conduit is sprung or turned in either direction.

This feature of tightly clamping the conduit is im ortant where the conduit as it generally oes, serves as a round conductor. Also,theclampin cofiar in addition 'erential contracting movements to conform to irregularities in the surfaces of the conduits and in some cases to threaded tapered ends, must be locked to prevent any movement, .particu larly turning movement of the conduit that would loosen the nut of the coupling and a ball and socket movement.

My conduit coupling solves all of the above-mentioned problems and comprises a threaded body having a passage for receiving a conduit end, a contractile collar mountab e on the conduit and and having a portion extending into the passage and a nut enclosing the conduit end and the collar and 35 threading on the body, the parts having coacting means for contracting the collar during the tightening of the nut, and the body and the collar having means for interlocking during tightenin of the nut to prevent turning of the collar and the nut if after the Joint is made, the conduit is turned.

It will be understood that in assembling the parts of the conduit system after the joint is made, the workman in making a joint at the other end of the pipe may put a pipe wrench on the pipe and turn it and in so doing, loosen the joint.

The body of the coupling is here shown for instance'instandard Z inch 55 I as a threaded nipple 1 provided on a con- 7 duit outlet box 2, although the body 1 may be independent of a box as 2 or the box 2 may be considered as part of a coupling be tween two conduits, I

The box here shown is provided with two threaded nipples 1 for connection to two difierent conduits.

- 3 designates the conduits, the end'oi each of which projects into a passage dot the body and preferabl abuts against an in ternal annular shou der 5 at the inner end of the body. I

6 desi ates the contractile collar mountable on t e end of the conduit 3. The collar is preferably. formed to tightly grip the pipe end without threading the pipe end.-

It is here shown as provided with cutting; projections 7 write internal'surface for cutend and-the collar and thrusting against the collar, the nut threading on the body 1. Means is provided forfcontracting the collar on the pipe end during thetightening of the nut and causing the threads 7 to into the threadless conduit end 3. -'l':he ....coacting -n1eans for preventing turning of the collar particularly retrograde turning it the corn duit end is turned, comprises projections and notches associated with the body and the collar and arranged to come into alinement and interlock during the tightening of the nut, this interlocking means being provided on abutting end portions of the body and the collar,

In the illustrated embodiment of my invention, the collar is provided with lengthwise peripheral projections 11 and the body with notches 12 in the end thereof around the passage 4, the notches being of greater widtthan the projections to permit the collarto contract after the projections are in the notches. The projections and the notches are provided with coacting .c'am

' means which act to contract the collar during tightening of the nut and as here illustrated, the rojections are provided with inclined end aces 12 which coact with comple mental inclined'faces 13 at the bottom, of the notches 12.

The principal means for contracting the collar is however, provided on the nut. and the projections, the nut being provided with an internal conical cam or conical face it at its outer end and the projections being formed with inclined faces 15 for coacting the bottom 'wa reases with the conical face 14, the faces 15 being of less inclination than the cam faces 12. It is these cam faces of different inclination that efiect the differential contraction of the collar to fit irregularities in the pipe ends and also tapered and also prevent a all and socket action.

In operation, the pipe end is first placed I in the passage 4 and the collar moved axially into the passage 4 and the nut tightened. Din-in V the initial turning of the nut, the collar 15 thrust endwise and turned until the projections 11 come in alinement with the notches 12 so that during further endwise movement, they move into interlocking engagcment with the notches 12. During con tinued tightenin of the nut 10, the collar is contracted b t e coaction of the conical faces 14 and inclined plane faces 15 and also by the coaction of the inclined cam faces 12 1 on the collar and the faces 13 at the bottom of the notches 12. As the nut is now tightened, the collar is tightly contracted on the conduit end 3 and conforms to irregulari ties of the surface of the conduit end and the threads or teeth 7 cut into the conduit end forging practically a threaded joint without previously cutting threads on the conduit 3.

After the joint is completed, it rigidly sup ports the conduit against all displacement and can not be loosened by the worman manipulating the conduit 3 as for instance, when he is coupling the other end ot the conduit to something.

What I claim is:

1. A conduit coupling com rising a threaded body having a passage or mceiv ing a conduit end, a contractile collar mountable 'on the conduit end and havin a portion extending into said passage, t e collar having a peripheral projectionand the body having a recess for receiving the projection and of greater width than the projection forv permittin the contractile movement of the collar an a nut enclosing the ipeend and the collar and threading on the body and means. for contracting the collar on the com duit as the nut is' threaded on the body.

2. A conduit coupling comprising an externally threaded body having a passage for Mid ice

receiving a conduit end, a contractile collar mountable on the end of the conduit and having a ortion extending into said passage and also aving a peripheral projection, t e body having a notch in its end for receivin the peripheral rejection, the projection an of the notch having coact ing cam means acting to contract the collar when the same is forced into the body and a nutthreading on the body and enclosing a conduit end. and the collar and enacting with the collar to thrust it amially into the body 3. A conduit couplin comprising an ex= ter'nally threaded body aving a passage for Maw 

